With the rapid development of technologies, different types of liquid crystal displays have been developed. The liquid crystal displays generally use liquid crystal display panels of various types such as a twisted nematic (TN)-type liquid crystal display panel, a vertical alignment (VA)-type liquid crystal display panel, and an in-plane switching-type liquid crystal display panel.
However, the issue of side-view color washout may occur when the existing VA-type liquid crystal display panel is viewed at a large viewing angle. The reason is that the light leakage phenomenon is not evident when the liquid crystal molecules of pixels in the VA-type liquid crystal display panel are viewed at a front-viewing angle; the light leakage becomes an evident phenomenon when these liquid crystal molecules are viewed at a side-viewing angle. In other words, the gamma curve may not be seriously distorted when the VA-type liquid crystal display panel is viewed at a front-viewing angle; yet it is seriously distorted, and for example, resulted in a Concave Function of the side-view gamma curve located above the front-view gamma curve, when viewed at a side-viewing angle. The distortion of the side-view gamma curve is more apparent at a low gray-scale level, and therefore the color washout phenomenon may occur in the luminance of the liquid crystal display panel when viewed at a side-viewing angle.
The method for solving the side-view color washout problem in the existing VA-type liquid crystal display panel is as follows: a single sub-pixel in the liquid crystal display panel is divided into two regions; a thin-film transistor (TFT) and a corresponding capacitor are used to divide a driving voltage, so as to drive the two regions using different voltages. Moreover, the two regions may have the same circuit area. The driving manner may be to turn on a first region (for example, a bright region) and then turn on a second region (for example, a dark region) of the single sub-pixel. After being properly designed, the front-view gamma curve of sub-pixels in the liquid crystal display panel may be maintained as the original gamma curve, and the distortion of the side-view gamma curve is reduced (for example, the difference between relative luminance ratios corresponding to the side-view and front-view gamma curves at a fixed gray-scale value is reduced). Therefore, the side-view color washout effect can be reduced by using the technology of segmenting a single sub-pixel into different regions in the existing VA-type liquid crystal display panel.
In the existing method for reducing the side-view color washout effect, the aperture ratio is decreased in the case that the circuit area of the sub-pixels is reduced (i.e., the pixel density of the liquid crystal display panel is increased). The aperture ratio is defined as dividing the luminous circuit area of the sub-pixels by the overall circuit area of the sub-pixels. The reason that the aperture ratio is reduced includes that when a single sub-pixel is divided into two regions, a voltage dividing circuit composed of a TFT and a corresponding capacitor is required to divide a driving voltage so as to drive the two regions separately. The voltage dividing circuit does not have the luminous characteristic, and therefore the presence of the voltage dividing circuit may result in the decrease of the aperture ratio.